The construction, calibration, and tests of a miniature four‐terminal thermocouple psychrometer are described. Improved thermal stability under nonisothermal conditions is the main feature of this new type of psychrometer. This is achieved using a separate thermocouple to cool and condense water vapor on the sensing thermocouple.
The sensitivity for this thermocouple psychrometer is about 0.4 μv/bar ‐ at 25C, and is operable at temperature fluctuations of about 0.5C during the course of a measurement.
In situ measurements of water potential in onion leaves under a cloudy day differed by 0.5 to 1 bar from measurements on detached leaves. With greater temperature fluctuations, water potentials obtained by the two methods differed by as much as 2 to 3 bars.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.